The purpose of this study is to determine the feasibility of providing personalized incentives for dietary self-monitoring and/or interim weight loss to people enrolled in a weight-loss program

In this study, community outpatients will participate in a clinician-facilitated, group-based behavioral weight-loss program for 24 weeks. Dietary self-monitoring data (input by patients via a mobile phone dietary application) and weight data (input by patients via cellular scale) will be collected by a software platform. A reinforcement learning algorithm will use data collected during the trial to predict which participants will respond to a financial incentive. Incentives will be provided to participants predicted to respond, and they will be notified of incentives via text messaging.

Inclusion Criteria:

1. Willing to attend virtual baseline and follow-up data collection visits
2. At least 18 years of age
3. Verified obesity as defined as a BMI ≥30 kg/m2
4. Agree to attend 13 biweekly group classes (virtual) delivered by a registered dietitian
5. Agree to review study materials between classes
6. Regular access to an unshared smart phone
7. Reliable access to internet
8. Able to speak and read English
9. Desire to lose weight
10. Able to connect to a video conference call using a smartphone, tablet or computer with a webcam and microphone
11. Ability to download and use Fitbit app daily
12. Have or be willing to create a Gmail address
13. Physical ability to stand on a scale without support

Exclusion Criteria:

1. Weight loss of at least 10lbs in the month prior to screening
2. Weight > 380lbs
3. Currently enrolled or enrolled in the previous month in a clinical, research, or community program focusing on lifestyle change that could affect weight
4. New user of weight loss medication
5. Pregnant, lactating or planning on becoming pregnant during the study
6. History of bariatric procedure or planning to have bariatric procedure in the study timeframe
7. Residing in a nursing home, skilled nursing facility or assisted living facility
8. Impaired hearing
9. Significant dementia, drug or alcohol abuse, or unstable psychiatric illness (e.g., schizophrenia, psychosis)
10. Current treatment for cancer or being treated for cancer (besides basal cell carcinoma or squamous cell) in the last 6 months
11. Use of insulin, sulfonylureas, or meglitinides due to increased risk for hypoglycemia
12. Diuretic medication doses higher than hydrochlorothiazide or chlorthalidone 25 mg daily, furosemide 40 mg daily, torsemide 20 mg daily, bumetanide 1 mg daily, or any use of metolazone; use of potassium-sparing diuretics is acceptable
13. Unstable heart disease in the 6 months prior to screening
14. Chronic kidney disease at stage 4 or higher
15. Exertional chest pain
16. Pain, fainting, or other conditions that prohibit mild/moderate exercise
17. History of ascites requiring paracentesis
18. Inducing vomiting to prevent weight gain or counteract the effects of eating an average of 1 time per week or more in the past 3 months*
19. Not suitable for study participation due to other reasons at the discretion of the investigators

This study will collect weight data from the cellular-connect scales, calorie logging data from the dietary tracking app, and self-reported survey data including demographics and behavioral measures. Additional data will include binary indicators for whether participants earned an incentive each week of the study and how much they earned, generated by algorithms created by the research team using scale and dietary tracking app data.

Scientific data will be available by the earlier of these two time points, as required by the NIH: 1) the date on which the article is first made available in print or electronic format, or 2) the funding period (to include a possible no-cost extension).